Reversible idler for conveyer belts



Oct. 20, 1959 M. KERECMAN ETAL REVERSIBLE IDLER FOR comm BELTS Filed Nov. 18. 1957 J fi INVENTOR. 6 MICHAEL KERECMAN ROBERT W. BRAUND ATTORNEY United States Patent 9 O .z,909,z72 REVERSIBLE IDLER on VCONVEYER BELTS Claims. (Cl. 198-202) This invention relates to self-aligning idler rolls for carrying the return flights. of conveyer belts and the like. It is more particularly concerned with self-aligning idler rolls which achieve this self-aligning effect for both directions of belt travel. 7

It is common practice to provide the lower or return flight of a conveyer belt with self-aligning idler rolls. These self-aligning rolls, sometimes called training rolls, automatically maintain the return flight of the belt in alignment with the rolls. A self-aligning roll commonly used is illustrated and described in US. Patent 1,833,180 granted to Samuel D. Robins, and our invention may be considered an improvement upon the article of the Robins patent.

The self-aligning effect of the idler shown in the Robins patent arises from the manner in which the single centrally-located bearing for the roll is pivotally mounted upon its axial shaft, as is there described. The bear-ing is pivotally mounted on a pin which is inclined in a certain manner with respect to the direction of belt travel, and the roll is self-aligning only when the belt moves in that direction.

It is an object of our invention to provide an idler roll which is self-aligning with respect to both directions of belt travel. It is another object to provide a selfaligning idler roll with a scraper device so disposed as to be effective regardless of the position assumed by the roll with respect to its pivoting pin. It is another object of our invention to provide an idler roll which automatically moves from a self-aligning position with respect to one direction of belt travel to a second selfaligning position with respect to the opposite direction of belt travel when the direction of belt travel is reversed. Other objects of our invention will be evident from the description and explanation thereof which follows.

An embodiment of our invention presently preferred by us is illustrated in the attached figures, to which reference is now made. Fig. 1 is a view in perspective of an idler roll embodying our invention and a portion of the conveyer belt supported by the roll, the belt and outer surface of the roll being broken away in part to make visible its interior.

Fig. 2 is an elevation of an idler roll embodying our invention.

Fig. 3 is a side elevation of the apparatus as shown in Figs. 1 and 2.

In the figures a conveyer belt 1 is shown as supported by an idler roll 2, the outer surface of which is a cylindrical shell. Roll 2 is journaled, in a manner to be described, on an axial shaft 3. The outer ends of axial shaft 3 are in turn journaled for limited rotary movement in bearing blocks 4-4, one such bearing block 4 being located at either end. Bearing blocks 4-4 are supported by structural framework 5-5.

On the extreme outer ends of shaft 3 are positioned collars 6-6. At one end of shaft 3 the collar 6 is rigidly attached to an arm 7 which extends radially outward with respect to roll 2. At the other end of shaft 3 collar 6 is attached to a rigid arm having one end 8 which extends radially outward in the same manner and parallel to arm 7, and projects in the opposite direction as arm 10 which may terminate in a handle 11. Between the outer ends of arms 7 and 8 is fixed a transverse bar 12 which carries a scraper blade 13. The scraper blade is adjusted so that its scraping edge just makes contact with the cylindrical shell of the idler roll 2. Supporting structure 5 at the end of the roll adjacent arm 10 is provided with a pair of projecting pins 15 and 16, respectively, positioned so as to limit the swing of arm 10 about the pivot formed by shaft 3. Pins .15 and 16 are so positioned that the arc of swing of arm 10 is symmetrical about a line through shaft 3 perpendicular to belt 1.

Idler roll 2 is provided internally with an antifriction bearing 18 in the manner shown in the Robins patent previously mentioned. The bore of antifriction bearing 18 is larger in diameter than shaft 3, which passes through bearing18, and bearing 18 is pivoted on a pin 19 which extends through shaft 3 transversely thereof; Arms 7 and 8 previously mentioned are positioned on shaft 3 so that they are parallel to pin 19.

The operation of our apparatus will now be explained, again with reference to the figures. Since the self-align ing action .of a self-aligning idler roll is described in the Robins patent above-mentioned, it will not be necessary to repeat it here. The scraping action of a scraper bar is, of course, well understood also, but the mode in which our scraper, bar operates on the surface of our idler roll requires some explanation.

Roll 2 pivots on pin 19 to the extent permitted by the clearance between shaft 3 and the inside wall of bearing 18. Because of this pivoting a scraper bar positioned directly below shaft 3, for example, and parallel to that shaft, will not operate properly and will interefere with the pivoting, and thus the self-aligning effect of roll 2. By mounting our scraper bar on arms 7 and 8, which are positioned on shaft 3 so that they are parallel to pin 19, we are able to obtain proper scraper action from our scraper bar 13 without interfering with the pivoting of roll 2. These effects are obtained only when the scraping edge of scraper bar 13 makes line contact with the surface of roll 2 in the plane defined by the axes of shaft 3 and pin 19. If the scraping edge lies in that plane, then it will not interfere with the pivotal motion of roll 2 because that pivoting will be about an axis perpendicular to the scraper edge. The scraper edge, of course, will not make full contact with the surface of roll 2 except when the axis of roll 2 happens to coincide with the axis of shaft 3, but as roll 2 swings across the edge of scraper 13, the latter will clean or scrape off the roll surface.

As has been mentioned, it is necessary that pin 19 be inclined to the direction of motion of belt 1 in a certain sense if the roll is to align the belt properly. Fig. l of our drawing shows pin 19 properly inclined for the direction of belt travel shown in that figure. If the belt is moving from right to left, as is there shown, over a rotating idler, then the idler must rotate counterclockwise and the pin 19 on which the idler pivots must be so inclined that an element of the belt first passes over the end of the pin further away from the belt and then over the end of the pin nearer the belt. It will be observed from our Fig. 1 that the direction of rotation of roll 2 is such that the scraping friction between the surface of roll 2 and our scraper bar 13 tends to urge arm 10 against stop 15; in other words, into a position in which pin 19 is inclined in the proper direction to permit self-alignment of the roll 2. Now let it be assumed that the direction of movement of belt .1 is reversed. The change in direc-' tion of movement of the belt causes a change in the direction of rotation of roll 2 and this reverses the direction of the frictional force between the surface of roll 2 and scraper blade 13 so that the roll surface 2 carries scraper blade 13 around with it, swinging arm away from pin 15 and in the direction of pin 16. When arm 10 is swung against pin 16 its further motion is stopped, and when arm 10 is in that position, pin 19 is moved into the proper position with respect to the new direction of movement of the belt to permit the roll to be self-aligning in that direction. Fig. 3 illustrates the apparatus of our invention moved into the proper position for operation with the belt traveling in the direction indicated in that figure.

Handle 11 may be used to swing arm 10 manually from one position to the other if it is necessary or desirable to move only one of a series of idler rolls for any reason or if undue friction develops in bearing blocks 4-4. In normal operation, however, our apparatus is moved from one to the other of two self-aligning positions by a change of direction of travel of conveyer belt and does not require any manual adjustment for this change.

We claim:

1. In the combination of a conveyer belt, an idler roll positioned in contact with the lower side of the belt, a shaft extending axially through the roll, and a bearing for the roll pivotally mounted on a pin transverse to the shaft, the improvement comprising a scraper blade fixedly connected to the shaft in contact with the roll surface, the blade being fixed so that its line of contact with the roll lies in the plane of the shaft and pin.

2. In the combination of a conveyer belt, an idler roll positioned in contact with the lower side of the belt, a shaft extending axially through the roll, and a bearing for the roll pivotally mounted on a pin transverse to the shaft, the improvement comprising means for mounting the shaft, means fixed to the shaft for rotating it in its mounting through an angle less than 180, and a scraper blade carried by the means for ro- 4 tating the shaft, the blade beingin contact with the roll surface and fixed so that its line of contact with the roll lies in the plane of the shaft and the pin.

3. The combination of claim 2 in which the means for rotating the shaft is provided With indexing means adapted and adjusted to position the pin at either of two rest positions in Which-ibis inclined at the same acute angle on either side of a perpendicular to the belt.

4. In the combination of a conveyer belt, an idler roll positioned in contact with the lower side of the belt, a shaft extending axially through the roll, and a bearing for the roll pivotally mounted on a pin transverse to the shaft, the improvement comprising means for journaling the shaft, a pair of parallel arms fixed to the shaft at right angles thereto, one at each end thereof, a pair of stops between which said arms swing, the stops being positioned to define two rest positions for the pin at equal angles on either side of a perpendicular to the belt, and a scraper blade carried between the arms in contact with the roll and adjusted to maintain its line of contact with the roll surface in the plane of the shaft and pin.

5. In the combination of a conveyer belt, an idler roll positioned in contact with the lower side of the belt, a shaft extending axially through the roll, and. a bearing for the roll pivotally mounted on a pin transverse to the shaft, the improvement comprising means for journaling the shaft at its ends, a pair of arms parallel to the pin fixed to the shaft at its ends, a pair of stops defining an are less than through which the arms swing, the arc of swing being symmetrical about a perpendicular to the belt, and a scraper blade fixed between the ends of the arms in contact with the roll and in the plane of the shaft and the pin.

References Cited in the file of this patent UNITED STATES PATENTS 

